nikko in 1 day?

Is it possible to visit Nikko only in 1 day? I mean depart from Tokyo in the morning, visit the shrine & temples and then also visit lake Chusenzi at same time. Need your advise if this scenario is possible since we have a very tight schedule. I really interest to visit nikko in autumn time during this trip.
Please also suggest, is the free pass tobu line really a better deal if only for 1 day trip?

thanks

We've been on a day trip to Nikko from Tokyo, starting from Shinjuku/Ikebukuro a bit past 7 in the morning, arriving in Nikko around 9, visiting the bridge, Toshogu Shrine and a few other shrines around it, took the bus up to one end of the Chuzenji Lake (the end closest to Nikko town)
and done a short walk by the Lake Chunzenji, and had a good look at Kegon Falls, at a no-rush, good comfortable pace. But note that in autumn, on weekends particularly, the place gets very packed, so plan carefully.

We've never bought the Tobu Nikko Free Pass, because we took the train from Shinjuku/Ikebukuro side. Once we got to Tobu Nikko, we purchased just the Chuzenji Onsen bus pass (2,000 yen). Even for one day, this pass covers all the bus rides from the station up to the Lake, free to get on/off anywhere within that stretch, and it pays off. I believe one-way bus ride from Tobu Nikko station to Lake Chuzenji cost 1,000 yen if you buy a single ticket.

The decision to buy the Tobu Nikko Free pass would depend on (1) whether you prefer to travel from Asakusa (where this pass is valid) or from Shinjuku (where it's not valid), and (2) considering the limited time you have on one day, you would want to take the limited express train, so how much the limited express supplement charge is in addition to the free pass cost (the pass covers only the local/rapid trains).

Thanks to AK for the information. Probably we will use JR pass from ueno station to utsonomiya station and transfer to jr nikko line. I read the one way trip takes about 100 minutes. From nikko station we will buy nikko free pass for the bus ride, as you suggested.
Could anyone inform, what time is the earliest train JR Tohoku Shinkansen from ueno to nikko and what time is the latest train from nikko to ueno?

thanks

To check train times, visit the reliable Hyperdia webiste. Just enter in your destination/departure points, time of travel, and voila.

This page has links to Hyperdia and other timetable websites:
http://www.japan-guide.com/e/e2323.html