Lance Armstrong -- Sorry Nike, I'm an ASICS Man Now

Lance Armstrong has GIVEN UP on Nike ... after Nike gave up on him ... 'cause the disgraced athlete was sportin' a pair of ASICS while jogging in Texas this weekend.

As we previously reported, Armstrong was dropped by nearly all of his sponsors last week ... in the wake of a report by the U.S. Anti-Doping Agency in which Armstrong is accused of being one of the worst cheaters in the history of sport.

In addition to being banned from cycling for life, Armstrong was also stripped of his 7 Tour de France titles early Monday morning.

Plus, several major Livestrong donors are calling for their money back ... claiming they were duped into donating to the charity "based on a fraud."

Despite the criticism, Armstrong -- who stepped down from his role as president of Livestrong because of the scandal -- wore his yellow bracelet on his wrist this weekend.