ONT is no longer a NEO-based token, having launched its mainnet in 2018. Your ONT tokens are hence not accessible within the Nash Extension.

However, ONT wallet addresses and private keys are identical to NEO wallet addresses and private keys. You can hence use the private key from your Nash Extension wallet to access your ONT tokens on the ONT blockchain.

One way to do this is:

1. Navigate to https://github.com/ontio/owallet/
2. Download the most recent Owallet version.
3. Open Owallet and select “Individual Wallet”. Hover your pointer over the “+” sign and click on “Import Wallet”.
   
   
   
4. Select from the list of options at the top the way you want to import your Nash Extension wallet. 
5. Enter the required information from your Nash Extension wallet, give it a name and click “Import”.
   
   
   
6. Select the wallet you just imported and you should see your ONT tokens there. You can choose to send the tokens to a different address but you will need ONG to pay network fees.
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Please note that this is only possible for ONT because its addresses and private keys match those of NEO. Any other tokens sent to the Extension will result in a loss of funds.