Spencer, the former Chelsea player who is now a rookie manager in the States, had tipped Forest boss Billy Davies off about the availability of Findley, whose contract with Real Salt Lake had expired, before the World Cup.
"John Spencer keeps me in touch with American players," Davies told thisisnottingham.co.uk. "He is now manager of Portland. He mentioned him to me in the summer and it all started from there. We are very pleased, he is a player people will have seen during the World Cup period.
"When we were alerted that he may want to try his luck in Europe, we immediately started to try to put wheels in motion. It was a race against time, because he did have other options.
"He is a goalscorer with electric pace and he will be a great benefit to our squad."
Davies believes Findley will hit his peak for the all important final few weeks of the campaign.
"He will be fresh for the final few months of the season, because he has had a little break now," said Davies.