"This is a really big club, and it's nice to come here knowing people," Nielson has told the club's official website.
"I know what they expect from me, and they will know what to expect from me. I am really excited because I know that they believe in me, so I will work hard for them.
"So many players would give their right arm to be in the position I am in right now. Of course it's an exciting time, and I am not going to let this chance go by."