Portuguese Empire

[CipKac]

There could be more flavor for an imperialist Portugal. Taking lands in moroccan coast (Ceuta from Spain, too, but mostly because of Tangier), reaching an agreement/personal union with Brazil through the Bragança-Orléans family at the expense of increased unrest and political debuffs/bad reforms (or just through puppeting as was already suggested by someone else). There's also South Africa, but taking that from UK would be a challenge for sure (that one i'm not so sure of, but that would be a good final boss to handle)

A portuguese move for the spanish throne would also be plausible. I'm not sure how that would fit in an event chain/decision though.