Sorry for your loss, but you cannot retrieve your key/mnemonic if you lose it. Chimera Wallet doesn't have access to your key/mnemonic and can’t help you with this. Ideally, writing your key/mnemonic down and storing it safely is advisable. However, if you remember your Password/passkey, you can use it to log in and retrieve your mnemonic from the app settings menu.
I lost my key/mnemonic. Help!
Updated yesterday