Nikki Bella isn’t just a former WWE Superstar … she’s a super-mom too — spending some quality time with her four-year-old Matteo after filing for divorce.

The former wrestler stepped out in Napa Valley Friday … taking her son to his dance class with a big smile on her face.

Check out the pics … both Nikki and her son look ready to work out — twinning in all-black, sporty outfits.

Nikki definitely participated in some self-care Friday afternoon … grabbing a couple green health drinks to cool off in the hot California sun — once again without her ring, no less.

Nikki’s outing came just a few days after she officially filed for divorce from Artem Chigvintsev … bringing an end to a two-week-long saga that kicked off after AC’s arrest for felony domestic violence.

As we told you … Artem called the paramedics to request medical assistance for the alleged victim before calling them off just minutes later. Police officers showed up anyway — per standard operating procedure — and arrested Chigvintsev.

Nikki stopped wearing her wedding ring almost immediately after the arrest … and, just before she filed, we broke the story that she was shopping for divorce lawyers.

NB asked for legal and physical custody of their son in her divorce filing … while also checking the box saying she’s open to Artem having visitation rights.