The 19-year old midfielder's stint at the City Ground has expired and he will now head back to Stamford Bridge after making 12 appearances for Forest.
Chalobah, who starred for Watford last season, scored two goals in seven starts for Billy Davies' side during his stay in the East Midlands.
The England U21 international made public his gratitude for Forest on his Twitter page.
Nathaniel Chalobah (@chalobah) January 15, 2014
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