Note: ChainX 2.0 and ChainX 1.0 are two different blockchains. You need to export the private key (which must be a private key) of the 1.0 wallet and then import it into the 2.0 wallet as following steps:
Install the Mathwallet extension wallet
ChainX 2.0 Browser extension User Guide
Import the wallet
Click “+” , select import wallet
Select the private key to import
Enter/paste the private key, select the Edwards(ED25519) encrypted version, and click Next to complete the import.
Note: The mnemonics in ChainX 1.0 wallet will not display 1.0 address after importing. You can export the private key after importing mnemonics in mobile wallet/web wallet.
More:
ChainX 2.0 Asset Management Dapps Guide
ChainX 2.0 Browser Extension User Guide
How to import ChainX 1.0 Wallet into ChainX 2.0 Wallet (Mobile)?