My 8 year old has been fighting us at bedtime: Thoughts?

My eight-year-old daughter, all of a sudden, is fighting us hard at bedtime. She has been going to bed by herself for years. (I tuck her in, and she goes to sleep within half hour-hour) Lately, she will not go to sleep, up every 5 minutes saying she can’t sleep, or every other excuse in the book. I stop letting her watch tv or any screen time whatsoever an hour before bed. Short of looking into melatonin for her, what can I do? I have tried every approach I can think of, and nothing is working. I have a newborn, so I am simply not able to sit with her in her room until she goes to sleep. Any suggestions would be greatly appreciated

If this is new, I am going to assume it has to do with the new baby. She probably just wants attention as it isnt just on her anymore. Try to include her in things that have to do with the baby!