It's pretty much impossible to get an exact pulse on how many people died indirectly as a result of the Fukushima Daiichi disaster evacuation specifically who would've lived if it were not for that. Particularly because most of the deaths attributed to the disaster were elderly to begin with.
Not trying to downplay the cost of human life, it's really terrible when preventable scenarios or mistakes lead to any cost. With that having been said, there are sometimes going to be events where evacuations are necessary, and some of them we can't prevent. No doubt there were many thousands of deaths unrelated to Fukushima Daiichi due to the massive earthquake and tsunami.
I believe it is estimated that around 1,000-2,000 people died as part of the evacuation efforts, but I am not sure what a good source is, so take that with a grain of salt. If you want to go really deep, it'd be wise to consider the burden that it may have caused psychologically too, but that's even harder to exactly ascertain, especially since it is likely nothing compared to what happened as a result of the earthquake and tsunami.
If the point of this is to compare safety though, factoring this in still would place nuclear fission power plants very low in terms of how much cost of human life they cause overall.