The 21-year old moved to the UK to join Everton in 2017.
He spent four seasons with the club before joining the Swans in 2021.
Defreitas-Hansen has also amassed nine caps for the United States' U16s and has also appeared three times for Denmark U19s.
The brother of popular Colls defender Luca Defreitas-Hansen, he has been on trial with the club throughout pre-season.
Discussing the move, manager Brad Cooke said: “I’m absolutely delighted with the signing of Nico! It wasn’t expected; we helped him find his feet after being released from Swansea, and after coming in with us he really enjoyed the environment, and he’s a player you simply can’t turn down.
“Nico has an unbelievable pedigree, with Everton, Swansea, the United States and Denmark, and for us to capture two exciting young professional footballers in the last week shows the progression of this football club.
“I have no doubt that Nico will have a great career as a professional footballer. Thankfully, we will be part of that journey!”
Photo Credit: Swansea City
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