Nikki Garcia (AKA Bella) looks happy doing the single mom thing ... taking her son to his dance class after getting a restraining order against his famous father.

Nikki was spotted Friday in Napa, CA for the first time since a judge gave her court-ordered protection from "Dancing With the Stars" pro Artem Chigvintsev.

She was smiling as she carried their son, Matteo, in her arms ... and they had matching all-black outfits.

TMZ broke the story ... Nikki beelined it to court this week and got a restraining order against Artem in the wake of his August arrest for domestic violence.

In a sworn declaration, Nikki claimed Artem "tackled me multiple times and pinned me to the ground while our child was present." She also claimed Artem got violent with her last year, grabbing her around her waist to keep her away from their son.

The restraining order prohibits Artem from contacting or coming within 100 yards of Nikki, Matteo, their home, etc. There is one exception, however, for visitation or exchange of the child per court-ordered visits.