France and Germany maybe.
Until Germany becomes a powerhouse, though (mid-late 1800s), they aren't much help.
If France still has a navy, maybe.
The problem is that Britain rules the seas, and can threaten the colonies at any time.
And, Portugal doesn't have much to offer in return.
I think Portugal could find itself some allies if it became stronger and/or played a smart diplomatic game. Until the scramble for Africa, Britain was the primary threat to Portuguese world interests. IF Portugal grew stealthily, and somehow diplomatically kept Britain at bay until, surprise, Portugal is relevant again, Portugal might make out better in the Scramble.
There's about 60 years between losing Brazil and losing in the Scramble. Portugal wasted a lot of those years in civil wars and recovery. All that energy needs to be channeled into infrastructure and development of Africa, so that when the Scramble occurs, Portugal can be at least on the periphery of the big boy table and can prevent the massive encroachment. OTL, they were simply pushed aside by all.