I think if it focuses more on the leadership part and less on the technical part, that kind of question will work here. You should specify the role more -- does it entail becoming a supervisor? Interacting with new parts of the organization or customers? Responsibility for a budget? I know what "technical lead" means in my company but it might not be the same in yours.
Part of your question is presumably about evaluating technical proficiency. We can't answer questions like "how do I know if I'm a good-enough programmer?" or "what skills should I learn?", but we can handle questions about evaluating technical skill more broadly. In fact, we've had those as interview-related questions, so look around there for inspiration.
Finally, you should specify in the question whether you're talking about yourself or one of your employees (e.g. if you're a manager considering promoting someone). The perspectives, and tools available, are likely to be different.