@misterflowers to understand the exchange value of money (and Nano, Bitcoin and USD are all types of money), you first have to understand what "money" really is. Money is a commodity that has come to be generally accepted as a medium of exchange. Because it is generally accepted as a medium of exchange, its value to a given person can be defined by the amount of purchasing power that it gives them relative to all other goods and services available.
The cost to produce it does not matter. We can see that by several examples. First, you gave the example that USD is somehow "pegged" to real value by the existence of a minimum wage. But labouring for an hour does not "produce" $7.25 worth of new, freshly-minted USD. Rather, labouring for that hour simply persuades someone to give you $7.25 of their existing stock of USD. When the Bitcoin emission process concludes and all 21 million Bitcoin have been produced, will the value of Bitcoin drop to zero or become impossible to calculate because it no longer has any cost of production? Of course not. It would continue to be exchanged at a similar rate, for the same reason that unbacked fiat USD are exchanged at a fairly stable rate. The exchange value of money is determined by past prices on the market itself. If I see that a loaf of bread cost $3 yesterday, and the day before, and the day before that, going back for over a year, then I can be fairly confident it will also be pretty close to $3 tomorrow. So, when someone offers me $12 to do a task, I can say to myself "well, I guess that would buy me about 4 loaves of bread". That is how people value money, by considering the past exchange values of of the money relative to the things they want to buy.
Because of this, the famous economist Ludwig von Mises argued that money must begin as a commodity exchanged on the market for some other purpose. For example, gold was used for jewellery and as a useful metal before it became money. As it became clear that gold was very durable and widely desired, it became generally accepted in exchange, and became "money". Once it functioned as generally-accepted money, people who had no interest in jewellery or metalwork would still value the gold, because they could exchange it more easily than anything else for what they actually wanted. This is how money first comes about, by having some pre-existing non-monetary value. Fiat currency like the USD starts out by piggy-backing on gold. At one time, the USD was really a receipt for a certain amount of gold. You could go to the bank and hand in your USD in exchange for physical gold that it represented. That link has now been cut, you can no longer exchange USD for gold. But because the system of prices in USD was already in place, and because enough people valued the USD for its exchangability apart from redeemability to gold, we have been able to keep using the USD without interruption (so far).
In the case of cryptocurrency (including both Bitcoin and Nano), I think the best way to understand the value that it had prior to becoming accepted as a general medium of exchange (that is, as "money") is its value as a payment network. PayPal is a very wealthy company, because they provide excellent payment-network services. Cryptocurrencies essentially compete with Paypal, Stripe, etc. to offer a similar service with lower costs of transacting. Those cost savings give people incentive to transact via Bitcoin/Nano rather than Paypal, and a side effect of transacting on the Nano network is that you need to use the Nano token. This is what creates initial demand for the Nano token itself. Over time, the price of the Nano token takes on a life of its own as it becomes widely accepted in exchange for a vast range of different goods and services, which collectively give exchange value to Nano.
Hope that helps. Money theory is fascinating stuff.
