yes that is true, Venzuela introduced the Petro coin which is a cryptocurrency with a limited supply and attached to the price of oil. It is supposed to replace the current currency Bolivar which has inflated to almost 1 million percent. However this is not a good example for two reasons. Next to the crypto currency will be also a traditional currency which is called the petro dollar. Also this will be attached to the price of oil. So it is actually a hybrid model, rather than that a fiat currency completely gets replaced by crypto. In addition to that, Venezuela has been quite harsh on crypto currencies, miners went to prison for abusing electricity, and the approach of the new currency is more a desperate act to stop the hyperinflation.

Here is a better example: Estonia

This small country is one of the most leading in terms of startups, it has mire percent of startups than any other country, the government is very open towards new tech and innovation and the city Tallinn is already a hub for blockchain companies. A while ago there were even plans to introduce a state issued crypto currency. These plans have been discarded though. In my opinion, there was peessure from the EU to let it go as it would have weakened the Euro. So if these forces were not at play, Estonia was probably the first country in the world.

Here is a source: https://www.worldfinance.com/markets/estonia-pushes-ahead-in-race-to-issue-first-state-backed-cryptocurrency