There are two common reasons your NFTs may not be visible in your account.
1. Right now, Oxalus Wallet just displays collectibles on Ethereum. Make sure that your NFTs are correctly on the chain.
2. Your NFT is beyond our support. Oxalus just supports displaying 23K+ Collections and still working hard to support all items or collections. Contact us via wallet@oxalus.io, or create a ticket on help.oxalus.io if you want to submit a new collection.