If you buy an NFT, you have to pay for it in cryptocurrency, and if you sell it you get paid in cryptocurrency. With regards to taxes, Skatteetaten treats NFTs the same as cryptocurrencies, meaning they are considered taxable assets. This means that both minting, buying, selling and ownership of NFTs will affect your taxes.
Income, gains and losses related to NFTs must be reported in your tax return with other cryptocurrencies.
Minting an NFT
Creating an NFT is called minting. This in itself is not a taxable event, but in order to mint an NFT you have to pay a small cryptocurrency fee.
When you pay this fee, you in reality sell a bit of your crypto. The crypto that you sell as a minting fee, you purchased earlier at some valuation. If that crypto has increased in value in the time between purchase and minting of the NFT, you have made a profit on that crypto. This profit is taxable. Likewise, if the crypto has decreased in value in the time between purchase and minting of the NFT, you have incurred a loss. This loss can be deducted from your taxes.
In summary: You have to sell a small amount of crypto to mint an NFT, and you should treat this transaction as any other cryptocurrency sale.
Buying an NFT
NFTs are exclusively traded with cryptocurrencies, so buying an NFT is considered a realization (sale) of the payment cryptocurrency. This transaction should therefore also be treated as a normal sale of cryptocurrency, just like when minting an NFT.
Selling an NFT
With regards to tax, selling an NFT is the same as selling cryptocurrency. If the value of the NFT has increased between your purchase and sale, you have made a profit. This profit is taxable. Likewise, if the NFT has lost value between your purchase and your sale, you have incurred a deductible loss.
As part of minting an NFT, a smart contract can be created. A smart contract can for instance define royalties to you as the original creator of the NFT. This means that every time someone sells your NFT, a certain percentage of the sale price gets paid back to you, just like a musician is paid a certain percentage of all sales of their music album. Such royalties are considered income and are taxable. Depending on the volume of your NFT sales, this might be considered to be a business. If this is the case, your royalty income should be taxed with other business income.
NFT and wealth tax
An NFT is inherently unique, and as such there is no simple way to determine what its true market value is. When you report your cryptocurrency wealth, NFTs should also be included. This means you are yourself responsible for estimating a realistic market value for any NFTs you own at the end of each year.
If you have a reasonable basis to estimate a market price for an NFT, for instance if it's part of a collection and expected to fetch a similar price to other NFTs in the collection, you report this value in your tax return. If you can't determine a realistic market price, you can report the purchase price as the taxable wealth value, meaning the price you paid for the NFT. Some people report the so-called floor price for the NFT collection as the taxable wealth value for their NFT, but please note this is not mentioned as an alternative in Skatteetaten's tax guide.
Also, keep in mind that you can't deduct unrealized loss on an NFT that you own. So even if you fomoed into a Bored Ape at peak hype, and that same NFT was only worth half at the end of the year, you cannot report this as a taxable loss until you actually sell the NFT.