I started googling for catchweight description and found this:
Another example was at UFC 99 when Wanderlei Silva fought Rich Franklin at a catchweight bout of 195 pounds. Silva typically fought at the Light Heavyweight weight class of 205 pounds, while Franklin fought at the Middleweight weight class of 185 pounds. They agreed on a catchweight bout, and both men weighed in at 194 for the fight.
This is my sick imagination, but Khamzat could easily sign a contract to fight Costa, as he is ready to step in against anyone. I like that you have mentioned welterweight and light heavyweight I like that I am not the only one who thinks that Costa is from different weight division than he is currently in. Khamzat is tall and quite skinny for welterweight. I think it wont be a problem for him to gain some extra pounds to punish Costa for trashtalk. But, I cant say that Chimaev could be an obvious fighter in that fight. Costa lands very heavy strikes, just like Burns. If Burns was enough to shake Chimaev and dispel the myth of Chimaev immortality, then Costa has all the chances to win Chimaev.
WOW! I never thought that it could be possible, and well Paolo Costa is originally in the Middleweight division alongside Israel Adesanya but because of his missed weigh-in against Marvin Vettori and he is heavier than a Middleweight the fight was shifted to the Light Heavyweight so he is technically a Light Heavyweight fighter now,
On that note, Gilbert Burns looks more like a Middleweight than a Welterweight but maybe his bodybuild also can compete with the Light Heavy aswell, so if Khamzat Chimaev withstands Burns, for me he can likely eat Costa Alive like said Chimaev is one crazy dude, he would do anything just to fight anyone he wants,
It's worth a punt on Diaz as you never know with him but the odds on Skybet are 11/2 which I wouldn't bother with. Both him and Chiamev are machines and don't give up and Diaz is like a Terminator so I think he will keep getting up and walking on into a war even if he's getting battered. I think Chiamav will win, but I could also see this going this distance as well. I would like to see an upset though. Will be interesting if Diaz does win and where that leaves him with the UFC. I'd still like to see the trilogy with McGregor some day. Connor is running out of options without taking on someone who is just going to annihilate him like Chiamev.
Well, an upset is only possible if the fight would not result in the ground, if Khamzat Chimaev decided to bring the fight to the ground then likely this may end up sooner, but knowing Chimaev he also wants to brawl just like he did with the Gilbert Burns fight, and Nick Diaz even though he is bloodied and brutally wounded he will surely get back up and will still fight this could also intimidate some of his opponents that is why it is going the distance, but for Chimaev he is known for the man with no fear, and Nate Diaz intimidation will not going to work against Chimaev,