Open your Chimera App
On the Home page, select the "Settings" button in the bottom-right corner
Then tap "Advanced Settings" in the Settings page
Tap "Delete Mnemonic"
Warning
Delete Mnemonic permanently removes your seed phrase from this device. After deletion, it will be impossible to retrieve your seed/keys from Chimera Wallet in any way. Be sure that you have backed it up in a safe place before proceeding.
A new window will open
Then tap the red button "DELETE" if you want to delete your mnemonic on your device