Again, npm is just a package manager, it is not a build tool. We use webpack, for example, to build the actual file we deploy. npm does not do that, it just gathers the required packages and handles dependencies. Actually building the project to deploy is another process.
If you open your Chart.js file and look at it, what do you see? Does it define a Chart object?
Yes, all of our servers use that environment. We have 7 servers online right now, as the CTO part of my job is running them. Our servers don't crash, but occasionally one fills up its hard drive or something else fun happens.
Why not download and save a copy of the file that you then serve locally?