Nicole Scherzinger. Mike Marsland/WireImage Nicole Scherzinger may have just finished tearing up the West End stage as Norma Desmond in Sunset Boulevard, but she hasn’t forgotten where she came from. “It was such a whirlwind,” Scherzinger, 46, exclusively told Us Weekly while reflecting on her time with the Pussycat Dolls. “It’s kind of crazy. So…