Nevada has literally tons of gold income. This gold is sold, so the state can pay its dollar expenses including debt service. The problem is that this exposes the state to the risk of a falling gold price (as has been occurring since May). The expenses remain the same, but the income falls. Refinancing in gold removes this risk.

It also allows the state to get out of debt at a discount. A paper describing the benefits of issuing gold bonds is here (https://monetary-metals.com/the-benefits-of-issuing-gold-bonds/