These two giants are finally going head to head.MercadoLibre (MELI 0.85%) and Nu Holdings (NU 3.84%) are top companies based in Latin America and are both reporting incredible growth. Until now, there hasn't been much overlap between them. But MercadoLibre just announced that it's encroaching on Nu's territory, with plans to open the largest all-digital bank in Mexico.Is this a threat to Nu's business?Nu is leading a digital-banking charge in Latin AmericaNu and MercadoLibre both offer fintech solutions for ...