Preheat your oven to 350 degrees.
The butter needs to be softened, so put it in the microwave for 30 - 40 seconds. It shouldn't be hot or boiling, but it should be liquified.
Using a stand mixer or handheld mixer, beat the butter with the brown sugar and granulated sugar until creamy.
Add the vanilla and the egg; beat on low speed until it just becomes incorporated – (10-15 seconds on low speed or so, don't over do it).
Sift together the flour, baking soda, and salt. Add it to the butter/sugar mixture, reserving about a 1/2 cup to the side. Mix on low speed until crumbles form. Use your hands to press the dough together into a ball. It will likely be wet and sticky so slowly add the reserved flour and continue pressing together. You are finished when the stickiness has subsided and and large easy to handle dough ball is formed.
Add the chocolate chips and the nuts and incorporate with your hands or fold in with a spatula.
Roll the dough into 15-20 balls (about the size of a golf ball or slightly bigger) and place on a cookie sheet.
Bake for 9-11 minutes. Trust the time and temperature. The cookies are finished when they look puffy and dry. Do not overcook. It's easy to be tricked into thinking they are not done yet. Dry nd puffy is what you are looking for.
Let the cookies cool on a wire rack for a half hour. You might be concerned by the puffiness, but they will sink down to a normal cookie as they cool.