The youngster’s move to the Pirelli Stadium will be the third loan spell of his career, after gaining first-team football at Shrewsbury Town and Doncaster Rovers previously.
A local lad, Ennis progressed through the Wolves system and made his first-team debut in a 2019 FA Cup replay against the Shrews at Molineux.
While spending last season on loan at Doncaster, the striker scored six times, and now returns to League One for more experience, this time with the Brewers.
The 21-year-old could make his debut in midweek against Rochdale and all at Wolves would like to wish Niall well during his loan spell.