Methodology Niche

Everything I’ve heard about niches is based on the assumption that the niche is the problem your coaching addresses or the customers you’re aiming at – eg, weight loss for doctors. But would it be just as good and viable to have as your niche not a customer type or a specific problem, but instead, a coaching methodology? Eg ‘I can help you solve *any life or work problem you might have* using my amazing, foolproof [insert type of Magic New Coaching Method/Approach here] technique?’ Is that still a niche? Does it count as one?

Thank you!