<Snipped quote by Menhir>
Presumption of Innocence allows a person to 'smell' a person's state of mind, their regular personality, and subconscious thought.
Unless this is all rendered through Mikhail's interpretation (and thus can be completely wrong), I think this is far, far too much information you would need from another person's character.
For example, if you objectively had olfactory knowledge of subconscious thought as well, you'd have to ask every single player you smell what they're really thinking if they didn't cover it in their post but you wanted to cover it in yours.
To put it concretely, Nico's general envy of others is a byproduct of his own self-loathing and inability to achieve anything noteworthy because he refuses to put genuine effort into most things. He's so certain he'll fail that he gives up before he even starts, and so he does fail most things and then writes it off as expected. Deep, deep down, he's aware he bombs things on purpose because he's scared of doing something right and doesn't want to be someone whom others expect anything from (because he's afraid he'll fail future expectations even if he succeeds in one or two things).
Can you smell that, too? Because then I have a problem with the ability.