MathWallet already supports adding custom NFT for all kinds of blockchains.
If your NFT is not loaded into your wallet by default. Here is a quick guide how to add custom NFT to your wallet.
Search NFT contract information
Normally you can find the NFT contract in the block explorer.
Copy the NFT Contract address
Add Custom NFT
Click the top right …
Then select ‘Add Collectibles’
Then select ‘Custom Collectible’
Paste the NFT contract to Contract Address field
Then you will see your NFT on the list.