Put a screw to hold that corner bead to the stud and then use drywall mud. I keep a bag of Easy Sand 5 in an airtight bucket. One bag got us through 14 years of three rather rambunctious kids. I think it cost about $15
The pink stuff is cool and all but it's expensive and dries out in the bucket
edit: you could just pick a bucket size, fill it with the hot mud and throw the rest of the bag away to still get more value than a homeowner ever will with pink stuff style spackle.