Microwave the cooked veggies

I have a busy schedule so I am cooking my veggies one day, then I am putting them in the fridge and I eat them the next days. I am using a microwave to warm them up on the next days. Is it ok or is it considered a bad practice (it destroys some valuable nutrients etc.)?

I don't see a problem with it since it's better than no veggies at all!

Depending on the vegetables, microwaving is actually one of the best ways to cook them in the first place because out of all variables 'total cooking time' is the thing that tends to destroy nutrients more than any other.

Also, everyone has this impression of microwaves as nuking your food, but microwaves don't use radiation in the typical sense. Microwaves are actually a form of light that has lower energy than even infrared--meaning that the visible light coming out of your screen right now is more powerful and "radioactive" than what you'll find in a microwave. Microwaves cook by vibrating water molecules, which creates friction, which creates heat.

Personally, I'm pretty busy myself and don't want to spend forever making dinner, either. So I get all my cooking veggies frozen, then microwave them as needed. Another thing that lowers nutrient content is how long veggies have been just sitting there. Frozen veggies are picked and then immediately flash-frozen which means all the nutrients get locked in. So frozen veggies actually tend to have a higher nutrient content than fresh (unless I guess you're literally picking it yourself and eating it immediately).

Just make sure you're cooking them properly since it can be easy to over or undercook them in a microwave

Yeah, from what I understand, microwaves are pretty safe for your food. And it's a good thing, because I also cook all my meals for the work week on Monday and just reheat in the microwave the rest of the week. 

All three responses above are solid advice. Microwaves are bad is "fake news" as Hillary Clinton would say. Bryce already explained why. 

I don't know if there are studies regarding how cooking vs microwaving affects the nutrient profiles of food, but I can tell you that from a chemistry perspective, "regular" heating and microwave heating are not the same/do not necessarily lead to the same outcomes chemically. There are reactions that you can make work with microwave heating that you can't with "regular" heating. That's despite Bryce's explanation above being on point. It's an active and not fully understood field of chemistry research. So that has me being cautious about microwaving my food. If you have a stove at hand and a single serving portion, heating your food on there really is not any less convenient (if a tad slower). Meaning a lot of times it is easy to switch between the two.