Use a sledgehammer to crack a nut
Definition 1 of 1
Pro Tip 1/3Figurative Use
The phrase is never about literally cracking nuts and always refers to an excessive solution to a simple problem. 
Buying the latest smartphone just for calls is using a sledgehammer to crack a nut.
Pro Tip 2/3Not Physical Force
The 'force' often refers to excessive measures, not just physical strength, like spending too much money or effort. 
Setting up a committee to change a lightbulb would be using a sledgehammer to crack a nut.
Pro Tip 3/3Often Negative
The phrase usually implies a criticism or disapproval of the excessive approach. 
They brought a whole team to fix the printer - talk about using a sledgehammer to crack a nut!