The developers of Nifty wallet have posted the following discontinuation notice on their website
Nifty Wallet is discontinued. As a result of changing crypto market conditions and to continually improve support for our growing family of Gnosis Chain products, certain existing products will be retired in 2022. This list includes the Nifty Wallet browser wallet. Nifty Wallet extension will be delisted from Google Chrome web store in the near future. (source)
A Nifty Wallet discontinuation notice will be added on the Sovryn wallet connection modal. Users will be able to continue to connect using Nifty Wallet until April 28, 2022. As of that date, Sovryn will no longer display Nifty as a wallet connection option.
Hardware wallet users should be able to use any Web3-compatible RSK wallet that has a hardware wallet integration. Just make sure that you are connecting using the same derivation path that you used with Nifty to continue using the same address(es). Note that you can also use your hardware wallet directly with Sovryn, with no need for any additional software installation.
For those who used Nifty without a hardware wallet, follow the below instructions to migrate your funds to a new wallet:
Warning: This method does not backup hardware wallet accounts or imported accounts.
Step 1. Select the menu at the top-right of your wallet.
Step 2. Select Settings
Step 3. Scroll down and press Reveal Seed Words
Step 4. Enter your Nifty wallet password
Make sure your computer screen is not in view of any third parties or cameras, to ensure that your seed words remain a secret known only by you. Remember that anyone who knows your seed words can gain access to your wallet and transfer all of its contents to themselves or anywhere else.
Step 5. Backup your seed words
To best protect the security of your seed words, do not copy them onto your clipboard or use the button that says “Save seed words as a file”.
Instead, if you have not done so already, write your seed words on a piece of paper, and store this piece of paper in a safe place, such as the same place you store other important / security-sensitive documents. Write down the seed words exactly as they are shown, in the exact same order, to ensure that you can successfully restore your wallet.
Step 6. Import your seed words into your new wallet
Download and install any Web3-compatible RSK wallet. We have some setup guides for a few compatible wallets here. When you’re given the option, rather than creating a new wallet, choose the option to import or restore from existing seed words, also referred to as a “secret recovery phrase” or similar in some wallets. Type in your seed words and make sure that your new wallet is using the same derivation path as Nifty to ensure you can access your already-used RSK address(es).
Nifty also offers the option to export individual private keys. If you are already using another wallet that also enables you to import individual private keys (such as MetaMask), this may be the preferable option so you can continue using your existing wallet and Nifty address(es) side by side.
Step 1. Select an account and click the 3 vertical dots.
Step 2. Select Export Private Key
Step 3. Enter your Nifty wallet password
Make sure your computer screen is not in view of any third parties or cameras, to ensure that your private key remains a secret known only by you. Remember that anyone who knows your private key can gain access to your address and transfer all of its contents to themselves or anywhere else.
Step 4. Copy your private key and import into your wallet of choice
To best protect the security of your seed words, do not use the button that says “Save seed words as a file”.
If you are confident you do not have any malware on your computer that is sniffing your clipboard, you can copy the private key to your clipboard and paste it into the import field on your new wallet. You could also paste it into a secure password manager app (e.g. KeePass) and copy+paste it into your new wallet at a later time.
Once you import the private key into your new wallet, you should be able to immediately access the funds in your address.