Travis Kelce's Ex Kayla Nicole Parties with 49ers WAGs in Las Vegas

Kayla Nicole's probably not rooting for Kansas City on Sunday ... instead she seems firmly in Niners camp -- partying with San Francisco wives and girlfriends

The ex-GF of Travis Kelce took to Instagram in the wee hours of Saturday morning to share a number of clips from a wicked rager she attended ... and a few familiar faces to 49ers fans popped up in the clips.

During the night, Kayla took a shot with some ladies ... and George Kittle's wife Claire threw one back alongside her. George of course is San Fran's tight end -- the same position Kelce plays.

Claire and Kayla are clearly friends ... having been photographed together at a different event near the end of January.

Kristin Juszczyk -- wife of versatile SF fullback Kyle -- tagged Claire in multiple posts last night from the party, so it seems she was there at least -- though it's unclear if she had any face time with Kayla as well.

Kayla's been fraternizing with people on both sides of the Super Bowl debate ... remember, we obtained photos of her and Patrick Mahomes' bro Jackson chatting amicably -- so maybe she's just being friendly to both teams.

Given her acrimonious breakup with TK, though -- and his new very public relationship -- we gotta imagine Kayla throwing back shots with Niners wives means she's chosen her side for the Super Bowl.

Rooting against your ex in the Super Bowl ... really adds a whole new meaning to "winning the breakup!"