minor butterflies could be big.
Obviously, no Napoleon is a major butterfly, but one of the ripples is the Jay treaty (1795). Sans Nap, the whole French revolution could be collapsing, which will affect Britain's willingness to negotiate with the US. The Jay treaty was a major reason Spain started to back down on US relations - giving up Natchez, for example, and wavering on the Mississippi navigation rights.
Also, you have to define an altered Napoleon. no Nap? or a different one. No Nap in Toulon may make for a completely different War of the Pyrenees. One of the generals went from Toulon to reorganizing the French army which then kicked butt on the Spanish. Spanish remaining in league with Britain also affects how much Britain is willing to back the US in conflicts with Spanish Louisiana.
Spain vs USA in 1790's/1800 with the Nap wars averted is a no brainer Spanish victory. I could picture New Spain keeping the southern zone, while the US gains the northern zone (or some of it. Britain is likely to freeze them out of the pacific northwest). New Spain was actually stronger than the US (or comparable) in that time frame, and was only torn asunder by the Nap invasion of Spain. They had also belatedly begun to strengthen the New Orleans region, and with time could have cemented their hold over the key mouth to the central water highway (Mississippi). The OTL kings of Spain doesn't lead to optimism, but it's not complete ASB to come up with a stronger New Spain with an altered Nap.