It’s hard to imagine Jackson would make a move that HoH Christie wouldn’t like — unless Jackson is just That Guy — so Christie must be OK with the idea of taking Kathryn off the block and nominating Kemi.
Big Brother 21 Episode 2 showed the formation of a six person alliance, and Jackson/Michie was in that alliance with Christie, Jack, Nick, Bella, and Holly.
(Not Tommy Bracco, even though he knew Christie going into the house; so Christie can keep him as a side alliance.)