The UFC Fight Night event will take place at O2 Arena in London and air on ESPN+.
Till (17-1-1) suffered the first loss of his career at UFC 228 in September, when he came up short in a title bid against defending champion Tyron Woodley. Till, 26, was caught by a big shot on the feet and tapped to a Brabo choke in the second round.
Fighting out of Liverpool, Till was 5-0-1 in the UFC prior to the loss.
Masvidal (32-13) was briefly linked to a potential fight against Nick Diaz on March 2, but Diaz ultimately declined the fight. Earlier this week, Masvidal publicly stated via social media he'd be willing to fight Till in his home country.
The co-main event could have welterweight title implications as well, as Edwards (16-3) is on a six-fight winning streak, including a decision win against Donald Cerrone last June. Nelson (17-3-1) has won three of his past four.