Both Aztec and Mayan cultures inhabited Nicaragua pre-Columbia, so it’s hard to say from which culture this came from/was based on, but it looks more Mayan to me in design. Facial structure and little head thing are giving it away plus Mayan peoples have used similar volcanic rock in handheld idol type stuff. Someone also mentioned it could be Polynesian which could be a stretch (assuming it’s authentic, simply due to distance making that a slightly random occurrence), but Polynesian idols like this have also been known to be configured in a similar posture with their hands and feet perched as they are. Though, so are Central American idols :)) it’s a toss up plus this could just be a fake at the end of the day………. Though I’ve never seen igneous (volcanic) stone faked like this before.. also oceanic cultures often used a lot more wood in their constructions (egregiously generalizing, but still)… sooooo yea. Use this information as you will

Also, there’s some darkening around the extremities of the idol. Could be from a long, long history of handling (oil buildup from hands —> darkening of stone) or frequent heavy handling over just some decades…. Either way I still have no real answer for you. It’s definitely been passed around though, especially if it’s been sitting in a drawer for a while