Patch the hole and re-Molly a little higher or lower and hope for the best.

Or:

Unzip the drywall on each side, install blocking between the studs to screw the bracket to, patch and paint the drywall to match. You'll have a rod you can do chin-ups from.

I'd do option two above. Otherwise. find studs and rehang rod there.

pull out old molly, stick a few toothpicks in the hole, patch with wood filler or wall patch filler, let dry, get a new, bigger molly and reset it.

Toggle is the way togo in a drywall wall with no stud

toggle bolts are molly on molly. : p

I had this problem, too. I wound up just putting up some Command hooks to hold up the rod. I wish I'd thought of it years ago, it's so much easier!

Toggle bolt for sure