Nikki Bella and Artem Chigvintsev are celebrating ... the first year of Matteo's life has been challenging for the new parents. During a November appearance with twin sister Brie Bella on The ...

Artem Chigvinstev has returned to Instagram ... posting a Reel filled with black-and-white photos of the dancer and his 4-year-old son Matteo, whom he shares with ex Nikki Garcia, 41.