i didn't nest, but i made sure i had everything bought and stocked before the baby arrived. i had two packs of size 1 diapers, and a mega pack of newborn. i also underestimated the amount of onesies we'd need, so i would say get at least two-weeks worth of those if you are starting with zero. you'll be changing that baby at least 3 times a day for the first week or two.
if someone wants to donate bottles to you, take them and just buy new nipples. you never know what will work. i liked ventaire, sis likes dr browns, and i started out with the drop ins. in the end, i spent so much trying out different bottles when people had been willing to give me theirs and i flat out refused. color me dumb (it dosnt matter thouggh because it works out in the end).
sign up for enfamil, gerber and similac online beforehand. you may never want to use formula, but the checks are good to swap with people for other types of coupons for pampers, baby food, baby store coupons, etc.. and if you DO decide to use formula, call the companies and ask for samples. samples last a good 3-4 days.
in my bag, i packed a bathrobe, two nightgowns, slippers and socks. i had a cesection, and panties were unnesessary. even with a vaginal birth, you get these GLORIOUS mesh panies. take extra at the hospital for when you come home. i wore the hospital gowns for the first two days, and wore a sports bra home and my maternity stretch pants. actually, i wore the same outfit i got to the hospital in (planned csection). everyone is different, but i didnt feel like overpacking and this was perfect.
toiletries are good to have. unscented deodorant, a hair brush, travel sized shampoos, conditioner and a toothbrush. i dont know about anyone else, but i didnt need to have my legs for a week after the baby was born because it was as if it stopped growing. that was a lovely surprise. one less thing i had to do.
snacks. granola bars, chips, juices, all helpful for the husband or partner while they wait for you to get things going.
phone and laptop chargers. in fact, store everyone you want to text in a draft in your phone so it's ready to go when you finally have that baby. the kaptop, some books, a kindle all come in handy when baby is sleeping ans oyu find yourself with nothing to do. sure you;ll be able to sleep a good sleep, but there will be a lot of quiet time, too.
and extra bag is also helpful for the swag you're going to be taking home. there will be gifts for the baby, diapers from the hospital, paperwork...those supermarket recycleable bags are good because they collapse if you end up not needing it.
your partner may need a pillow and blaket if he/she decides to stay overnight with you. also recommend a change of slothers for them as well, and comfortable lounging PJs.
you get 3 months of amazon prime free when you sign up for amazon mom, so it's also worth looking into if you have not yet done this.
i miss my hospital stay. i know there are a lot of people who cannot wait to get out of there, but not me. i made the most of it. good luck!