When we have already defined Chart of Accounts we could now assign it to a Company Code. As it was already mention, we could assign one Chart of Accounts to several Company Codes. This is one of the prerequisites for maintaining uniform Controlling Area within several Company Codes.
IMG Path: Financial Accounting (New) -> General Ledger Accounting (New) -> Master Data -> G/L Accounts -> Preparations -> Assign Company Code to Chart of Accounts
When you open the transaction. Find you company code and fill the already defined Chart of Accounts.