Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.
In a large mixing bowl, combine 1 cup creamy peanut butter and 1 cup packed light brown sugar. Mix until smooth and creamy.
Add 1 large egg and 1 teaspoon vanilla extract to the peanut butter mixture. Stir until fully incorporated.
In a separate small bowl, whisk together 1 cup old-fashioned rolled oats, 1/2 teaspoon baking soda, and 1/4 teaspoon salt.
Gradually add the dry oat mixture to the wet ingredients, stirring until just combined.
Fold in 1/2 cup semisweet chocolate chips evenly throughout the dough.
Using a tablespoon or cookie scoop, drop rounded spoonfuls of dough onto the prepared baking sheets, spacing them about 2 inches apart.
Gently flatten each cookie slightly with the back of a spoon or your fingers.
Bake in the preheated oven for 10 to 12 minutes, or until the edges are lightly golden but the centers remain soft.
Remove from the oven and allow the cookies to cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.