Heat a Dutch oven or large skillet over medium heat. Add bacon and fry, stirring occasionally, until bacon is crisp, 5 to 7 minutes. Transfer bacon to a paper towel-lined plate.
Drain all but 1 Tbsp / 15 mL of bacon grease out of the pan. Return pan to medium heat.
To heated pan add chicken and saute until just cooked through, 4 to 6 minutes. Transfer chicken to plate with the bacon.
To heated pan, add butter and asparagus. Saute for 2 minutes to start asparagus cooking.
Pour flour over asparagus and stir until no dry spots remain. Pour stock into pan while whisking. Bring stock to a simmer and simmer until stock reduces and thickens slightly, 3 to 4 minutes.
Add heavy cream and simmer for 1 minute more.
Add pasta to the pan and stir everything to combine.
Remove pasta from heat and stir in pesto, peas, chicken, and crispy bacon.