Chris Matthews, now embraced by tout liberalisme, used to gut Clinton on a nightly basis.
This is what drinking at places called Klutch on a nightly basis will do to you.
See Katie Couric as the first female nightly news anchor as proof.
Old English nihtlic "nocturnal, of the night, at night;" see night + -ly (1). As an adverb, Middle English nihtlich, from the adjective.