The fleet-footed 19-year-old is highly-rated by Royals boss Alan Pardew who is keen to give the youngster a taste of first team action with chances at the Madejski Stadium limited.
"I am pleased to have signed Nathan until the end of the season and I am sure he will do a good job for us," coach Steve Cotterill told the club's official website.
"He is very quick and his main asset is his pace. He has done well in the reserves at Reading and when he went on for the first team against Brighton recently he apparently gave them a real strong run for their money.
"He is young as well which means that with so many games coming up he will recover quickly.
"I would still like to bring in another player and I am waiting on a couple of calls. We will just have to wait and see."
