The 25-year-old, who stands at 6ft 8in, has joined Forest on a four-year deal, pending a work permit, which runs until the summer of 2028.
Miguel told the Forest website: "I'm really happy and honoured to represent this club.
"Just seeing the stadium and feeling the energy within it, I can't wait to be on the pitch to help Nottingham Forest win."
Miguel admits Murillo had an influence on his decision.
"Yes, absolutely, the first information came from Murillo.
"I asked him about the club and also the city. I asked how the club works as it's so important to know everything beforehand.
"He said great things and was exuberant about this club, which made me really happy."
Miguel also said: "It was important, really important.
"Coming genuinely from a friend who moved here from Brazil on his own for a new challenge the way he did.
"He only had good things to say, I trust him and believe this is the place for me."