Settle Jews in the New World very early on, preferably in lands that have a high carrying capacity with very low starting populations of hunter-gatherers. South Africa, the La Plata region, the Chesapeake, the Hudson, etc. are all decent options. As a poster above mentioned, one way could be to have a different start to colonialism that favors penal colonies; as a result rather than expel the Jews, Spain instead settles the Jews in the New World in the least profitable colonies or establishes new penal colonies for this purpose, so far away from the Caribbean and the equator. Have the relation between this colony remain mutually beneficial between this alternate timeline Spain and the Jewish-dominated colony, such that Jews begin to actively seek to migrate there of their own volition. Additionally, having this colony be politically and economically dominated by Jews will apply social pressure on non-Jews to convert openly or adopt aspects of Jewishness in social settings that creates a 'Jewish' superculture for the colony(as far as the rest of the world is concerned) even among those who aren't Jews by religion in the longterm. Between steady immigration and naturally high population growth, this Jewish populace would swell massively. Assuming that this colony is in an economically significant region(the Cape, the estuary of La Plata, etc.) then disproportionate economic prosperity when compared to a colony of another group can be assumed due to this colony having deeper market penetration with the rest of the world due to the long-established Jewish trading networks that can be coopted easier than other groups could manage. A colony in South Africa especially would be a boon for disrupting old Silk Road trade routes as well as having a much easier means to funnel aspiring Jewish settlers from the Middle East without the oversight of the colonial overlord; it could easily lead to a Boer situation where there exists independent states outside of immediate control of the colonizer state if said colonizer tries to crack down on migrants that aren't pre-approved.
Using the timeline Portuguese America and Southern Africa TL as an inspiration here, the booming population in Southern Africa could result in a situation where effective control of trade, shipbuilding, and manpower for a section of the Empire is more or less entirely sourced from the Jewish colony, which would help build it up, give the Jews a higher standing with the crown, and also make a potential independent state far, far stronger. So going off of the idea of a Spanish Jewish Cape that blobs over Southern Africa as in the Portuguese Southern Africa TL, the Indian Ocean trade could be coopted by Jewish manpower and shipbuilding sourced from the Cape assuming Spain still manages to have its manpower strained between its colonies, wars in Europe and the Mediterranean, etc. AFAIK Jews weren't used as soldiers, but it's feasible to imagine them serving as sailors, especially if Spain is in a tough situation. If this happens early enough, you could have the language of commerce in the Indian Ocean be supplanted by TTL's Judeo-Spanish/Ladino much like Portuguese IOTL, further spreading Jewishness around the world. Anyways, any aspiring trader will likely be Jewish or speak a Jewish dialect.
Next, colonies in the Indian Ocean and the Pacific. With a large manpower pool and the trade network to transmit colonists already establish, any potential colony by Spain in the region could be sourced by Jewish South Africa. Or a particularly entrepreneurial Jew may establish trading posts that build up from there. Long story short, it's entirely plausible that the land down under is in part or fully settled by Jews, especially if Spain is proactive in its colonization efforts. Assuming this were to happen, you've now turned the Indian Ocean into a Sephardic Jewish pond; any Spanish adventures in the region will be entirely dependent on their Jewish subjects, said Jewish subjects will have a higher social standing that will (likely) improve their lot in other Spanish colonies and Spain itself, etc. If we assume this is some wacky variant on Portuguese America and Southern Africa and Spain is a united Iberia, then it's plausible to imagine Spanish trade posts in India being established, maybe a conquest of Ceylon, spearheaded by Jews. In this situation you could see some amount of syncretism by the conquered towards the conqueror's religion as well as intermarriage; you could plausibly have a sizable population of mixed Jewish-Indian descent numbering in the millions by the present day. Ditto for other regions where the Portuguese adventured about in Asia.
Assuming that Spain snowballs as hard as it did in Viriato's TL but the Old World arm of the Empire outside of Europe is entirely ran by the Jewish arm of the empire overtly or indirectly through soft power, then Arabia, East Africa, and the Persian Gulf are all fair game too. Anyways, assuming Spain botches it(see: OTL for endless examples) and the Jewish colonies secede, then the trade empire is likely to go along with it due to Spain proper not having much if any real control over the Indian Ocean aspects of its empire, having largely profited off of trade flowing in via the Cape. One failed campaign to reconquer South Africa later, the various Jewish colonies are informally aligned politically, definitely aligned economically, and depending on the state of the Middle East, it becomes plausible to see Jews conquering Egypt and the Levant from the Red Sea, especially if you can spin it ideologically. Anyways, long story short, Jewish Indian Ocean and Pacific and a massive population of Jews. Plus an even larger population of people that could be considered Jewish if you squint, or belong to 'Jewish' culture in the same vein as almost all Americans 'know' what 'White' culture is but can't for the life of it define where it starts and where it ends; the Judeosphere will have bled some elements of Jewishness into the cultures of the conquered as well as its neighbors, as well as converted a small number of individuals over time.