I don't know if I agree with that sentiment. I think Collaros was the better QB of the two. He is absolutely more aggressive and at times was willing to throw the 50/50 ball and trust his guys. He was very accurate deep. If you think Nichols went through his reads a bit faster, I think you need to consider that Nichols has been in this offense for five seasons and Collaros had five weeks.
Four seasons, actually*. LaPolice joined this team in 2016, at which point Willy was the starter and ultimately lost it to Nichols during that season.
Collaros played four games for this team and did a really good job executing the playbook. His best trait was his ability to scramble and make plays with his feet, adding a nice wrinkle for opposing defenses to consider. By no means did his stats jump off the page or anything, though.
Regardless of sample size or tenure, Nichols has executed this offense very well far more often than not, which is backed up by the numbers over that period.
IMO, it's not necessarily reasonable to compare the two QBs but consider this (FWIW): during this 2019 campaign, Collaros posted a 105.7 QB rating in his four games played; Nichols, in his 9 games played, posted a QB rating of 107.2. While neither QB blew the doors off any opposing defense, both were highly efficient and smart with the ball.
*
Bellefeuille was OC when Nichols was acquired in 2015