Well, an innovator equal to Bud Powell maybe. But equal to Monk? That's absurd. Nichols is generally considered to have been a fine composer, but he didn't record much as leader and his partisans are still trying to bring his work into the mainstream. I have the box set Herbie Nichols: The Complete Blue Note Recordings. It's a fine collection, both in terms of composition and in terms of down right compelling piano work.Composer and pianist Herbie Nichols’ inquisitive spirit lives on amongst a growing group of young followers, and in the spirit of every jazz musician who struggles to cultivate an individual sound within the din of the marketplace. An innovator equal in powers to Bud Powell or Thelonious Monk, he spent most of his career working in bands whose music was less adventurous than his own.
One jazzman who has championed Nichols' work is Roswell Rudd. Unfortunately, Rudd is an acquired taste on his own. If Nichols is to get his spot in the spotlight, it might not be Rudd who does it for him. But The Unheard Herbie Nichols is worth a listen.
Here is a sample of Nichols, playing his most famous composition.
And here is a cut from Rudd's tribute: