Maggie Nichols just laughs when asked if she plans on asking Under Armour where her check is. “I should, right!” the retired two-time world championship medalist and two-time NCAA all-around champion said. Nichols is kidding. Well, mostly. She didn’t complain when the athletic apparel giant approached her in 2016 about appearing in an ad that also featured Madison Kocian and MyKayla Skinner. Despite being high-profile elite gymnasts with world championship gold medals on their resumes, they were amateurs at the time the spot was filmed. Taking money would have technically made them professionals and jeopardized the college scholarships that awaited them once the 2016 Olympic cycle was complete. So they hung out. They were treated like movie stars for a few days. And they didn’t receive a dime. It was good exposure. It was good fun. Looking back, though, Nichols isn’t sure that it was a good call. “It’s upsetting …