In a large mixing bowl, combine the sour cream and ranch seasoning mix until well-blended.
Fold in the drained diced tomatoes with green chilies and shredded cheddar cheese.
Transfer the mixture to a serving dish and garnish with chopped green onions before serving.
Notes
For extra spice, add a few dashes of hot sauce or chopped jalapeños to the dip. This dip is best served chilled with tortilla chips or fresh vegetables.