Lombard would toss Nick around like a rag doll.
Would watch.
..until Lombard gasses and Nick beats the absolute fuck out of him.
If it's a 3 rounder then Lombard can win a decision, but if it's a 5 rounder then Nick is going to give him a beating that resembles his days in Strikeforce.
In a 5 rounder, Lombard is guaranteed to gas out eventually. Nick is extremely good at making his opponents tired. Once Lombard gasses, Nick will have a lot more success with stopping his TD's and he will bully Lombard.
Gassing against Nick is literally the worst thing that can happen. Even in a 3 rounder, Lombard would still gas but he'd definitely survive until the end and take the decision. That's not to say Nick can't possibly win a 3 round fight, but I'd pick Lombard to take it, just like I'd pick Nick to take a 5 rounder. Lombard cannot hold that pace, he will gas, he will get smashed, he will lose, badly.
Even in a 3 rounder, Lombard's only way of winning is LnP. He won't be able to do anything on the ground because Nick's defense is too good and he's extremely active from his guard - no, Lombard will not pass his guard. On the feet, Lombard throws 1-2 punches at a time unless his opponent is offering nothing on the feet at all. Lombard is extremely predictable on the feet, his speed and power has brought him a long way, but he doesn't do anything on the feet that will make Nick
not be able to get his rhythm and beat him there.