There's a list of
English-speaking Services on the U.S. Embassy homepage. See "Munich (Bavaria) attorneys", there are 2 lawyers mentioned in Nürnberg: Dr. Günther Kreuzer,
www.kreuzer.de and Wolfgang K. R. Distler,
www.ra-distler.deBoth list labour law among their fields of work, and Kreuzer also "Ausländerrecht".
A "Kündigungsschutzklage" needs to be filed within 3 weeks after receiving the notice.