I find Nim less safe than Rust because its unsafe features aren’t segregated in any way. Both languages have unsafe features, and those are necessary to interface with C or to implement low level functionality. But Rust has the brilliant “unsafe” keyword — unsafe language features and C APIs can only be used inside a block tagged with “unsafe”, and a function whose behavior is unsafe can be tagged “unsafe” so it can only be used in an unsafe block.
What this does is make it very clear what is safe and what isn’t. That’s a big help with code and security reviews, lets you make better decisions about what 3rd party libraries to use, and can help you avoid accidentally compromising safety of existing code when modifying it. I wonder how hard this would be to add to Nim? At a first glance, unsafety seems like an attribute that could be tracked at the function level by Nim's existing effects system. But the compiler would need to know to add this effect when any unsafe language construct is used.
