Sync passwords from 2 different iCloud accounts (2 Keychains) How can I copy all of my keychain passwords to another keychain? I have two  different Mac computers with two different iCloud accounts.
You can export your Keychain item(s) to a file from one computer and then import that file into the Keychain to your second computer using Keychain Access.  Apple has step-by-step instructions on its Support site:
Import and export keychain items using Keychain Access on Mac