In a large pot over medium-high heat, melt the butter. Add onion, celery, and poblano pepper; season with salt and pepper. Cook, stirring occasionally, until the onion softens, about 7-8 minutes. Add garlic, chile powder, and dried oregano, and saute for about 1 minute until fragrant. Add chicken stock and potatoes. Bring to a boil, then lower heat to simmer. Cook until potatoes are tender, about 15 minutes. Stir in frozen corn, heavy cream, and sugar. Cook for 5 minutes until warmed through. Transfer 1½ cups of soup to a blender and purée until smooth. Stir back into remaining soup. Add cotija cheese, cilantro, and lime juice. Season to taste with salt and pepper. Serve garnished with additional cilantro, cotija, chile powder, and crema. Serve with lime wedges.