Impeachment, should it occur, won't be limited to Trump+Ukraine. But as for Trump+Ukraine, what's the metric that defines a nothing burger...?
Senate fails to convict? That's a given no matter the facts, no matter the law.
Impeachment fails to move public opinion? Maybe even backlash? Who knows. Trump's robust portfolio of impeachable acts, including Trump+Ukraine, are in a different league entirely from Clinton's actions. But on the other hand, Trump's base is perfectly willing to interpret "Nice place you got, shame if something happened to it" as a genuine statement of concern. We're in uncharted territory and it's high risk for all concerned. I don't see a basis for exuding confidence -- in either direction.
Or maybe nothing burger means Trump actually did nothing improper. That's risible, given his and Guiliani's admissions, and the known facts concerning Biden.