I have no idea who will win this. Till was able to control Gastelum in the clinch briefly and shuck off most of his TDs, but Brunson is bigger, stronger, and arguably a better MMA wrestler. Bobby went 2 of 13 with his TDs against him and didn't do anything with his successes in Rd 5. I could see Brunson doing better than Kelvin or Robert and controlling Till on the ground like he did Holland for the first half of the fight and surviving late... or I could see him getting outstruck and pieced up to a Decision/TKO loss.
One thing worth noting is how each guy's last few opponents/camps is actually ideally suited for facing the other. Till has done nothing but train and prepare for aggressive, high-pace wrestle-boxers who would want to take him down (Vettori, Hermansson, Gastelum) since coming to 185 which is worth noting. Conversely, Brunson has spent his tidy little streak embarrassing various technical kickboxers with good footwork and knockout power (Holland, Shahbazyan, Heinisch, Theodorou).
Brunson is a known quantity... we just haven't seen enough of Till. Even at Welterweight, he never faced a high-level MMA wrestler willing and able to ground him repeatedly. Now at 185 he's even more of a ???? in many ways. I have more faith in him than most, but I still have no clue about this fight.