(According to Billboard) One rapper replaces another atop The Billboard 200 this week, as Nas' untitled Def Jam album dethrones Lil Wayne's Cash Money/Universal set "Tha Carter III." Nas' album sold 187,000 copies in the United States, according to Nielsen SoundScan, becoming the rapper's fifth No. 1 here. Nas' prior album, 2006's "Hip-Hop Is Dead," also debuted at No. 1 but sold 354,000 over Christmas week. Meanwhile, after three non-consecutive weeks at No. 1, "Tha Carter III" slips to No. 2 with a 15% sales decrease to 105,000.