Heat skillet over medium heat. Cook bacon 5 to 7 min., or until crisp. Transfer to paper towel-lined plate to drain. Cool completely; finely crumble. Reserve 1 tbsp (15 mL) bacon fat from skillet.
To make dressing, whisk oil with vinegar, maple syrup, mustard and reserved bacon fat; set aside. In bowl, mix broccoli slaw with kale. Set aside
Fill four 2-cup (500-mL) Mason jars (or 4 tall, narrow re-sealable food containers), by layering ingredients into jars in the following order from bottom to top: dressing, tomatoes, chicken, onion and slaw mixture. Seal jars and store refrigerated up to 24 hr.
Let stand at room temperature 10 to 15 min. before shaking well and serving.
Substitute chopped Romaine or iceberg lettuce for the kale.