When reading the responses, it seems like everyone is reactionary but there are some good points made. I will say that I am answering this question as a home inspector and previous to that worked in the insurance industry as a Loss Control consultant. Also I am in California but inspections and insurance carriers are similar.
First the major damage referred for repair is vague in your description. I can think of so many possibilities from crumbling, cracking, water intrusion, rotation to name a few. I would hope the insurance representative has pointed to it and showed it to you and you agree it is major or is it just something talked about on a report. Most people are not qualified to evaluate foundation but when it is major, I would think we would all be able to understand it when it is pointed out.
Now going back to when the house was purchased, was the area where the damage is, was it some how concealed? Basement full? Was that area cleared prior to your purchase and did you walk through? So could the home inspector have seen it or was it concealed? You might also talk to neighbors to see if the previous owners had discussed any foundation concerns. Neighbors have been good sources of information to me in the past.
The reply asking why the insurance company inspected the house is a good one. I know from my experience that this may be completed for high value homes and homes that had previous history of claims. Does either of these fit your house?
Lets also consider the qualifications of the home inspector and the inspector for the insurance company. As I said above not everyone is qualified to evaluate foundations. After becoming a home inspector, I realized how little I understood for some items like foundations. I have personally seen people improperly call out problems that were not or were not significant. That does not mean I am siding with either person.
How would I suggest you proceed? Attorneys are not the first step. Call your original home inspector to come back out and look at this finding. Many inspectors are going to want to know what is happening and most contracts state you need to inform them if there is a concern with their inspection. Second, considered getting an third opinion. That will give you better understanding and if you ever need to go down a legal or arbitration route. You can hopefully discover how big the problem is or is not.
If there is a confirmed problem, your real estate agent should be consulted. Many larger real estate firms have in-house legal counsel that may be able to help understand what your options may be.
As I suggest here, there is a little investigation that may give better clarity.