Is Dual nano sim feature available in USA Iphone 12 pro max models ?

As per the related article: In China mainland, Hong Kong, and Macao, certain iPhone models feature Dual SIM with two nano-SIM cards.

You can use an eSIM instead. More on this page: Using Dual SIM with an eSIM - Apple Support

No. The only phones that take 2 nano SIMs are those sold in China, Hong Kong, and Macau.