You could add another level of nesting:
Expression < 0 ? 0 : Expression
where expression is the entire statement you currently have.
Or - slightly unorthodox - add another derived column transformation after this one and you can build another expression using the column you have just created. Avoids the nasty nesting.
If you haven't even tried to resolve your issue, please don't expect the hard-working volunteers here to waste their time providing links to answers which you could easily have found yourself.