Is Western involvement critical in solving this problem? I don't get a feel the Nigerian Army feels that way. They've already met the Sri Lankans, so that should tell you in what direction their minds are moving.
This doesn't surprise me, and one the reasons I'm a vocal critic of U.S. COIN doctrine. It doesn't work, and yet we seem to be the only ones who don't recognize it. We promote political correctness over combat and strategy effectiveness. There are many options for countries to consider when it comes to security advice, and it is only logical they'll turn to a country they perceive to be successful. Tactically the Sri Lankan approach may work, but ultimately I suspect it will only the make situation worse. The Sri Lankan approach doesn't facilitate consolidating the victory in a way that leads to an enduring peace.

On the other hand, the U.S. isn't as competitive as it used to be when a country is looking for security assistance. The exception is when the U.S. is throwing money at the country (buying influence). It's sad if we're not sought out for our strategy and military competence. I suspect that is gradually will erode our influence globally as we lose our competitive advantage. When countries are facing existential threats they'll seek approaches they think will work. We need to find a better balance between promoting our ideas, morals, etc. with military effectiveness.

Final point, we create our own asymmetric disadvantages with our excessive legalistic approach to war.