In a food processor add together the basil leaves and lemon juice and pulse 3 to 4 times on high. Next, add in the cheese and pine nuts and pulse 5 to 6 times. Note: everything should appear finely minced and you may need to scrape the sides a few times with a rubber spatula. Next on high speed, slowly drizzle in the olive oil until combined. Season with salt and pepper. Once the eggs have been hard-boiled, cooled and the shells removed, cut them in half longways and place the cooked yolks into a large bowl and repeat until all of the yolks are in there
Add the yogurt to the egg yolk bowl and thoroughly mix with a whisk until smooth.
Next, add in 1½ tablespoons of pesto and adjust the seasonings with salt and pepper and then chill until completely cool. Once the filling is cool, add it to a piping bag and squeeze a small amount of it into each ½ hard-boiled egg until all of them have been filled. Garnish by adding a small amount of the remaining pest to each pesto deviled egg and sprinkle on some fresh chopped chives. Completely cool before serving.