The Extension of Eligibility blanket waiver allowed anyone eligible in 2020 to have 6 years to play 5 seasons of ball instead of the normal 5 years to play 4
Nix and Daniels played 5 seasons in just 5 seasons.
Taulia Redshirted in 2020 and didn't use a Season of Competition that year. He has a 6th year to play his 5th Season of Competition
https://umterps.com/sports/football/roster/taulia-tagovailoa/11051
As a Redshirt Sophomore (2021):
As a Sophomore (2020): Started in all four games he played in
It's the same reason Xavier Watts has 2 years of eligibility left after redshirting in 2020 as a freshman