Place the water, garlic slices, and a pinch of salt in a large saucepan. Bring to a gentle simmer over medium heat, ensuring the water is hot but not boiling.
Add the chicken breasts to the simmering water. Cover the pot and reduce heat to low. Cook for 15-20 minutes, or until the chicken is cooked through and tender, showing firm white color at the edges and a gentle poach movement.
While the chicken is cooking, prepare the salad ingredients: halve the cherry tomatoes, slice the avocado into thin pieces, and roughly chop the basil leaves. Arrange these ingredients in a mixing bowl.
Remove the cooked chicken from the poaching water using a slotted spoon. Let it cool slightly before shredding or slicing into bite-sized pieces. Add the chicken to the bowl with the vegetables.
Drizzle the olive oil over the salad ingredients and season with salt and pepper to taste. Gently toss everything together until evenly coated and combined.
Serve the salad in individual bowls, highlighting the vibrant colors of the tomatoes, avocado, and basil. The tender chicken pieces complement the creamy textures, creating a visually appealing and balanced dish.