I suppose it depends on what the help was, and what it led to.
If the Portuguese were providing gunpowder weapons and organisation - it could both help them win, and then help with consolidating royal power, and with that, allow them to go on the offensive against the Oromo, and perhaps shatter those migrations.
It really depends on the character of Portuguese help - and the environment around it. If Ethiopia are able to produce/import gunpowder and create weapons - they'd be a great ally - able to secure the Gulf of Aden for Portugal, and expand down the coast.