Since she is nearly 3 years old she is going to cut down on her sleep time. That is her entire day and how many hours of sleep she needs.
If you are putting her down at 8 and expecting her to sleep until at least 8am then have a 2 hour nap that is WAY too many hours of sleep for a pre-school age child.
Toddlers and infants still need more sleep but once a child is 2 or 3 they are going to need less sleep.
She should still lay down after lunch and rest. Obviously her body needs it or she wouldn't be falling asleep. Kids that are not tired do not fall asleep.
So adjust her bedtime to when you want her to wake up. If you want her up at 6am to go to child care then you'd want her to go down early in the evening. If you want her to sleep until 8am or later then you'll want her to go to bed around 9 or 10. 10pm-8am is still 10 hours of sleep.
Pre-school age children do not sleep more than 10 hours at night. Then take that nap during the day because they're tired and that nap combined with the overnight hours is over 12 hours of her day asleep.
12 hours + sleep per day is too many hours of sleep for a nearly 3 year old child.