I don't know much about FrDave Nix. I never heard of him before Mass of the Ages. I'm sure he's a smart and generally doctrinally sound priest. I don't watch or listen to his content. Someone informed me that he has weighed in on the John Salza Pints with Aquinas (Matt Fradd) interview calling it "silly". I checked the post and commented.
He sounds like he is a schismatic in training, if not already one himself. I wouldn't follow this blind "leader" into schism any more than the blind leaders who stay within the Catholic Communion. They are wrong for different reasons which is a distinction that emotion based Trads have a hard time making. Lesser of two evils won't work for you here because the perceived lesser of two evils here, participation in, support of, promotion of the SSPX and all similar setups, takes you out of the Catholic Church and into a schismatic "church".
There's only one Catholic Church, outside of which, there is no salvation.
*UPDATE: Since I knew very little about FrDave Nix, a friend sent me this telling article about him: https://www.catholicnewsagency.com/news/39512/denver-archbishop-releases-letter-responding-to-claims-by-priest