Whether due to his rabid fan base or well-chronicled psychogenic vomiting, Wilco frontman Jeff Tweedy’s psyche is plumbed every time he walks onto a stage. Judging by Tuesday night’s performance at the Lincoln Theatre, things are going pretty well for the shaggy, self-effacing singer. After years of struggle and mid-level success, his band has outgrown the confines of critical-darling status, now enjoying the spoils of widespread recognition and the type of reliable, ever-increasing fan base that encourages a band to release its own brand of coffee. In short, Tweedy (the singer) is doing just fine.