The problem is that the plantation economy set up by Portuguese, Castillans and Aragoneses in the XVth was reliant on slavery (altough not only chattel slavery) and a semi-enserfment to undergo a cash-crop production, essentially sugar (that was mostly implemented in Valencian region,then Grenada, as a financially interesting production (with a significant support from Italy.
While slavery in Atlantic islands, then Americas tended to be significantly harsher and bloodier than in late medieval Spain and Portugal (which still tended to takeover the old slave trade roads that Arabo-Andalusian and Arabo-Berbers beneficied from, by-passing them by sea), it set the exemple and practices which were put up to eleven in Carribeans and Mexico (especially trough the technically semi-servage but real enslavement known as encomiendas).
So, short to butterfly away the medieval market economy and first capitalism...What could we have? Maybe a significant reduction of slavery in medieval Spain, possibly but it's far from an obvious consequence, an earlier reconquista and a deeper development of manorial management of plantations (a bit like in Aragon and with the permanance of salaried slavery) added with a North African and/or Sahelian ensemble strong enough to prevent an efficient Christian takeover of African slave in a first time (oceaning by-passing is still going to happen).
If you add to this an harsher time to takeover Mexico, if it's conquered at all, then you might have the grounds for alternative, more manorial-based productivity. But sooner or later, the sheer profits involved are going to make slavery really tempting.