You can find a lot of varying estimates, based on other varying estimates, and they're almost always from a source with a vested interest in skewing the statistics one way or another.
And numbers for accidents caused by windmills?
Here's my attempt at nuclear vs windmills (except I'm only mildly biased in the pro-nuclear direction and trying to be as fair as possible):
The vast majority of nuclear power plant deaths occurred from Chernobyl. This has been estimated anywhere from 57 deaths to 985,000 deaths. Obviously these numbers are both BS. A realistic estimate appears to be about 5,000. (See Have several hundreds of thousands of people died because of the Chernobyl disaster? )
Since 1965, nuclear power plants worldwide have generated about 69,602 TWh, if you add up all the totals from BP Statistical Review of World Energy 2011
Together, this is 0.07 deaths / TW⋅h = 630 deaths / TW⋅yr
CWIF lists 99 windfarm-related fatalities up to to 31st December 2011. Some of these are dubious (car accidents caused by distraction from shadows), but there are certainly others unreported, so we'll just use that number.
It's really hard to find a single statistic for the total amount of energy produced by wind. Wind advocates always quote "installed capacity" because it sounds bigger, but that's just the maximum theoretical power a wind farm could produce under constant high wind. The actual amount of energy produced in reality is less than 1/4 of this.
Combining several incomplete sources (EIA, Paul Gipe, IEA, WWEA) that seem to match each other more or less, and extrapolating for 2011, I get a total of 2400 TWh total since 1980.
Together, this is 0.04 deaths TW⋅h = 360 deaths per TW⋅yr
So based on (pretty imprecise) death estimates, nuclear still has to catch up with wind.
As I said in a comment, the Next Big Future source is being dishonest by extrapolating the nuclear numbers 25 years into the future and assuming no accidents during that time, which they don't do for other power sources.