Nelson, 18, signed a long-term contract with parent club Arsenal, before making the temporary switch to play under the Bundesliga's youngest head coach during the summer transfer window.
"A loan wasn't always my first option, but when I heard the Bundesliga and Hoffenheim was an option for me and working with the manager there, it was something I wanted to do," Nelson told The FA website.
"Julian's a great manager and he's got belief in young players so it's a good place for me to go and play. He's very young, he's only 31 and I think it's important to go to a team and a coach who believes in you, so he was the main reason, because he is willing to play us."
Following in the footsteps of Borussia Dortmund's in-form teenager Jadon Sancho - recently called up to the England squad for the first time - and English winger Ademola Lookman, who spent the second half of 2017/18 on loan at RB Leipzig, Nelson has already made four appearances for Hoffenheim this season.
He has scored two goals in three Bundesliga outings, including one on his debut, and also got his first taste of UEFA Champions League football in the 2-2 draw with Shakhtar Donetsk in September.
"I've settled in well and I'm enjoying it," Nelson explained. "My dad is German, too, from near Munich, so I knew what to expect and I'm learning the language with an app called Babbel and it's going well."
Nelson is currently on international duty with the England U21s. He netted another debut goal as the Three Lions booked their place at next summer's UEFA Euro U21 championships, courtesy of a 7-0 rout of Andorra.
Nelson, who will return to Arsenal at the end of the 2018/19 campaign, could get his next slice of Bundesliga action against promoted Nuremberg on 20 October.