Yes, MILLER is a Scrabble word!

Letter values in Scrabble US: M 3, I 1, L 1, L 1, E 1, R 1.

Is it a valid word?

MILLER is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

United States bandleader of a popular big band (1909-1944)
United States novelist whose novels were originally banned as pornographic (1891-1980)
United States playwright (1915-2005)
someone who works in a mill (especially a grain mill)
machine tool in which metal that is secured to a carriage is fed against rotating cutters that shape it
any of various moths that have powdery wings

Also: glenn miller, alton glenn miller, henry miller, henry valentine miller, arthur miller, milling machine, moth miller.