This must be the absolute easiest possible way to make a nightgown. I started with a pair of pillowcases.
Someone gave me these and I love the print, but I have already made plenty of pillowcases for my bed, so these will become a nightgown instead. I also found part of a coordinating pillowcase in my scrap bag, left over from a previous recon.
This is just enough fabric for me to use to make the chest band and straps for my nightgown. You could use whatever you can find in your stash; you won't need much.
So, you start by cutting the pillowcases. Remove the side and bottom seams to make two flat panels.
Then sew these panels together at the side seams, lining up the hemmed edges, which will be the bottom of your gown.
Then make your chest band. Measure your chest, above the bust, under the armpits. Make the band as you would binding, by pressing in half and then pressing the raw edges under 1/4", and then sew the short ends together to make the band.
Now set your machine to its longest stitch length and sew a basting stitch around the raw edge at the top of the gown. Pull on the bobbin threads carefully to gather this piece to fit your chest band. Encase this inside the band, pin, and then topstitch all around to attach the band to the gown.
The last steps are the straps. Sew them right sides together and turn. Then you will pin them to the gown and try it on to determine placement before you sew. Once you are happy with where the straps sit, sew them in place on the inside, near the top of the band. Clip your threads, and you're done!