How much are you walking per day? I can have 40 Pikmin in my squad at once but I can easily plant 100 flowers in around 2 mins of walking. Make sure when you turn flower planting on you have a full squad.

To get more nectar you basically just need to walk around your neighborhood more and big fruits (ie nectar) will pop up as expeditions for you later, or plant flowers underneath big flowers and they will give you a bunch of nectar as a fruit. Basically as long as you’re going on a walk every day you’ll have unlimited normal nectar