rat's nest

feather one's nest

To achieve benefits, especially financial ones, by taking advantage of the opportunities with which one is presented; to amass a comfortable amount of personal wealth; especially, to do so to a degree that involves venality.

give a rat's arse

To care a minimum amount; to have or show minimal interest

hurrah's nest

pandemonium (state of chaos and confusion).

leave the nest

To leave home; to stop living with one's parents.

love nest

A residence, especially a condominium or cabin, where a couple (particularly a newly cohabiting or married couple) can enjoy each other's company.