If Chance continues his interest in mounting and sniffing Kiya's "female parts", there could be something else going on. It is not unusual for female pups to get puppy vaginitis. This ailment produces aromas that male dogs mistake for being in season. (People can't smell it.) Left untreated, the male dog will aggravate the female so much that fights can occur. I use an ecchinasea/goldenseal capsule daily, opened and mixed with something "smelly" to hide the bitter taste. The problem is always resolved within one week. I am not a veterinarian though so you should discuss this ailment when you take Kiya to your vet.
And Robyn is right, this could be the problem also, however in knowing Chance and seeing his behavior with other dogs, I think much of this is that he is just very inmature for his age and never really learn "proper" play with other dogs… he is not aggressive to other dogs, he is just inappropriate with some of his antics.... Kiya, given the chance will put him in his place... but I would think this house is going to get really loud with Basenji sounds...