Red Nichols was obviously influenced by Bix. On recordings he made before he had heard Bix (such as George Olsen's "He's The Hottest Man In Town" and "A New Kind Of Man" from mid-May and early June 1924, respectively) his solos/breaks are strikingly different (devoid of any Bixian feel) to how Nichols played after first hearing Bix.
Red talks about the influence of Bix in Nat Shapiro and Nat Hentoff's "Hear Me Talkin' to Ya". I'm sure many forumites will be familiar with this quote, but it is worth repeating it again: "Bix made a tremendous impression on me, and I'd be the last to deny that his playing influenced mine. But I did not consciously imitate him. I had already evolved the "style" identified with me in later years, and the same was true of Bix. We both derived our inspiration from many of the same sources. Only a person who is musically ignorant finds any MARKED (my capitals) similarity between my work and that of Bix."
I certainly think it unfair to accuse Nichols of plagiarism. Red Nichols' own comments above seem reasonable and balanced in assessing the impact of Bix on his playing. And Nichols was certainly quite capable of forging his own path as a jazz and dance band musician. Though he was influenced by Bix artistically, Red didn't need Bix to succeed commercially.
One might assume that Bix picked up one or two tricks from Nichols, but there is scant evidence for this. Even the rips and half valving that are often associated with Nichols were first played (at least on record) by Bix.
Also in "Hear Me Talkin' To Ya", George Johnson (of the Wolverines) states: "From the very start we were quite well received, and the word got around Broadway that the Wolverines at the Cinderella were something new and different. Famous musicians came to listen and were eager to sit in, just as we had been in the days of Friar's Inn in Chicago. Most frequent of these was Red Nichols, who at that time was just coming under the influence of Bix's genius. Red probably will not like this statement, but it is my personal opinion that much of Red's playing today is the direct result of the absorption of ideas gained from listening to and playing next to Bix, together with the learning, note for note of Bix's recordings. Even before we had landed in New York, we had heard a recording of Red called "You'll Never Get to Heaven with Those Eyes" in which he used Bix's chorus in "Jazz Me Blues" note for note."
If Nichols himself is hesitant in stating that Bix was a major influence, it is because he was understandably irritated by constantly being compared to him, and being judged on that factor alone. Jazz history has pushed Nichols into the shadow of Bix, despite the fact that Nichols was his own man who often outshone his contemporaries when soloing. In turn, he inspired many of his fellow musicians to play solos that were as sophisticated and polished as they were hot.
Many black musicians were deeply influenced by Louis Armstrong, yet they are rarely judged harshly for this fact. So why is Nichols dismissed because Bix was a major influence on his playing? It isn't a crime to be influenced by a musical giant like Bix, who let's face it changed the direction of how jazz was played amongst his peers, just as it isn't when it comes to being influenced by Armstrong. And we certainly don't criticise Sylvester Ahola or Norman Payne for being influenced by Bix, so why is Nichols judged so harshly? Is it because Red had the temerity to be commercially successful early on and maintain a Bixian style over a long and fruitful career? If so, this hardly seems fair.