Before 1971 dollars were backed by Gold, now they are backed by US Tbills (and some real-estate since 2008).
It's not that different.
Gold and US TBills are both valuable assets.
What the OP meant by creating money out of nothing was fiat currency, which we do have now.
If you decide to use a commodity also as money, that's fundamentally different, and econ textbooks can confirm this for you.
T-Bills are backed by fiat currency, not by a commodity.
The Fed, and also the banks through fractional reserve banking, genuinely do create "money out of nothing."
Check out A Monetary History of the US by Milton Friedman and Anna Schwarz. Here you will find a Nobel Prize winning econonist who wanted to dramatically reign in, or even end, the Fed and get rid of fractional reserve banking.
TBills just bonds. They are 'backed' by the US Governments credibility to pay back the loan.
USD is generally backed by an asset - fractional reserving not withstanding.