1 cup butter, softened
1 cup packed light brown sugar
1/2 cup white sugar
2 eggs
2 teaspoons vanilla extract
1 1/4 cups all-purpose flour
1/2 teaspoon baking soda
1 teaspoon salt
3 cups quick-cooking oats
1 cup chopped walnuts
1 cup semisweet chocolate chips

Preheat the oven to 325°F (165°C).
In a large bowl, cream together the butter, brown sugar, and white sugar until smooth. Beat in eggs one at a time, then stir in vanilla. Combine the flour, baking soda, and salt; stir into the creamed mixture until just blended. Mix in the quick oats, walnuts, and chocolate chips. Drop by heaping spoonfuls onto ungreased baking sheets.
Bake for 12 minutes in the preheated oven. Allow cookies to cool on baking sheet for 5 minutes before transferring to a wire rack to cool completely.