Question

"A lot of noise and no walnuts" idiom sentence​

Answer 1

She said that she will call the police if those people ever bother her again, but she didn't. She's a lot of noise but no walnuts.

Hope this helped.

Answer 2

A lot of noise and no walnuts refers to those people who talk a lot about something  but never actaully does it.

it is a spanish idioms.

An idiom is a phrase or expression that typically presents a figurative, non-literal meaning attached to the phrase; but some phrases become figurative idioms while retaining the literal meaning of the phrase.

so basically these are those phrases whose literal meaning are different from the actuall meaning.