Sweden is too small, got started too late, and has too many interests elsewhere to hold territories on the North American continent in the face of opposition from any other colonial power. (I assume you mean the continent - grabbing a Caribbean island a few decades earlier doesn't seem that challenging, or that intererstig.)
The trick, then, is IMO to avoid said opposition. If the Dutch lose New Netherland in the first Anglo-Dutch War, than New Sweden will have some breathing room, although it will be surrounded by English territory to the north and south, and given the relative sizes of the colonies, it is likely to eventually be to the west as well. But Sweden and England were often on friendly terms in this period due to Dutch support of Denmark-Norway and Swedish-Danish rivalry.
While the Swedes could not hold New Sweden in any war with England, they might be able to preserve their colony through a mix of friendship and appeasement and prevent any such wars from occurring in the first place.
This probably means a lot less support for France, who was both Sweden's patron/close ally and England's colonial rival OTL - and that's probably the biggest hitch in the process - but if New Sweden becomes important enough to change Swedish foreign policy in other areas, and England provides more of the subsidies France did OTL, New Sweden might be able to persist. It's probably not the likeliest course of events given the PoD, but it seems to me a plausible one.