It is not Spanish but Galician; 'miñaxoia' is something like "my jewel", but it is understood as a condescending way of calling a person who is naive, inocentona, without malice. See Galician/Miñaxoia , good guy .
It means naive, silly, rédula person, candid. It is a Galician term and would literally translate as "my jewel".
Miñaxoia Literally my jewel, in Galician. It is said of the naive and innocent person, who becomes a little silly.