Jamie Foxx — Rides Bruce Jenner’s Nuts

Jamie Foxx killed with Bruce Jenner transition jokes at the iHeart Radio Composition Awards.

Foxx hosted the award show Sunday night in L.A. … and in his opening monologue he teased the upcoming musical acts, saying Bruce Jenner would be performing — “He’s doing a his and her duet all by himself.”

The jab scored big laughs — Chris Brown was particularly amused — and Jamie went back…