Heat a large skillet over medium-high heat and pour in a tablespoon of olive oil. Once the oil shimmers, add the frozen tilapia fillets. Cook for 10-11 minutes, flipping halfway through, until golden brown and flaky.

Reduce heat to low. Pour in heavy cream and pesto, stirring to combine. Mix chicken broth with cornstarch until smooth, then add to the skillet. Simmer for 3-5 minutes, stirring occasionally.

Stir in lemon juice. Taste and season with salt and pepper. Return tilapia to skillet, spooning sauce over it, and warm through for an additional minute.

Remove from heat and serve immediately. Pair with mashed potatoes, pasta, or a fresh green salad.