Salt the fish fillet and allow to sit refrigerated for at least 20 minutes to firm up the flesh. In a mixing bowl, add fish, lime juice, 1 teaspoon salt, tossing to coat. Marinate for about 30 minutes, tossing occasionally until the edges of the cubes turn opaque.
Add remaining ingredients, except tortilla chips, to the bowl and adjust seasoning, making sure to add avocado at the very end so as not to smash it. Serve with fried tortilla chips.