Tyson, 30, has not started a game for the Rams in over two months, since the 2-2 draw at Middlesbrough at the start of October, but has scored three crucial goals for Clough's side after stepping off the bench, including winners at Ipswich and against Birmingham.
"The difference in Nathan is the confidence to get those goals, which started when he scored against Sunderland in pre-season," Clough told the club's official website.
"Since then, he's looked a different player and far more confident. Even when he's not been playing he's been ready when we've needed him coming off the bench and more often than not, he's made an impact and got us a goal."
Clough added: "It's been a bit of a toss-up in recent weeks between Theo (Robinson) and Nathan starting games, but on we've been going with Theo because he's been among the goals lately.
"However, Nathan is getting his fair share himself and he's very close to starting games and he's given us a dilemma that is for sure."