In her Field Guide to Birds, Carolyn Hedge Baird recommends Chain Stitch as one of only a few stitches great for outlining. I agree and I love to use and recommend it for thick outlines.
There’s little problem with it if the line is straight or curvy. But what if your area has corners or points? Making them sharp can be difficult.
In this detailed tutorial Mary Corbet shares her method to make Chain Stitch points.