Preheat oven to 350 degrees. Line a baking sheet with parchment paper.
Add the pecans to a small skillet and toast over medium heat until fragrant. Stir and continue toasting for 1 more minute.
Remove nuts to a cutting board and finely chop.
Add the butter, brown sugar, white sugar, egg, and vanilla to a mixing bowl and beat until well combined.
Stir in the flour, baking soda, and salt until a soft dough forms.
Mix in the toasted pecans and toffee bits.
Portion dough into 9 large balls and space evenly on the prepared baking sheet.
Press the chocolate chunks into the tops of the cookie dough balls.
Bake for 11 minutes exactly. Cookies may look underdone but will continue to set up while cooling.
Cool completely on baking sheet before transferring to an air-tight container. Cool at least 5 minutes before eating or cookies will fall apart.