Insert a new drywall screw 1 inch directly above or below every nail pop. Countersink the screws slightly, but not so deeply that the heads of the screws tear the surface paper covering the drywall.
Remove loose drywall paper tape, the old corner bead and bits of dried compound with a 4-inch putty knife. If the bead was nailed on, you’ll need to pull those nails out as well.
Sand the wall corner after removing the old corner bead to smooth down rough patches.
Spray corner bead adhesive on the inside flaps of the corner bead and position the bead over the wall corner. Press and smooth the flaps against the wall.
Apply a coat of premixed joint compound over the corner bead, smoothing it on with a 6-inch taping knife. Use light pressure, just enough to spread the compound along both sides of the new corner bead.
Switch to a 12-inch taping trowel and further smooth out the wet joint compound. While it’s easier to use the smaller blade for the initial application, the larger blade spreads the compound over a wider area, making it less noticeable.
Smooth a little bit of the compound over the old nail pops and the new recessed screw heads, and remove large clumps of excess compound from the wall with the taping trowel. Let the compound dry completely.
Sand the wall corner with a drywall sanding pad lightly. Dried compound sands away easily, so use only light pressure.
Apply a second thin coat of joint compound to the corner and over the nail pops, using the same method you used the first time. Let dry, apply one more coat, sand, and then paint the wall.