As far as I know, there is no support for custom constantly changing (sensor) data in the Eddystone specification. The implementation in Nordic's SDK reflects the specification, and the only way to add or update data is via the Eddystone Configuration Service. Typically you use Google's Beacon Tools app for that. You could of course modify the Eddystone example to include the accelerometer data, but it may not be handled consistently across clients as it will be non-standard.
It depends on how you want to do it. You have to do it in a application specific way since it is not supported by the Eddystone specification. I do not see any good way of doing it, at least not if you want it to work out of the box with normal Eddystone clients (e.g. an Android phone with no custom app).
How do you intend to use this in practice? How will the clients/phones etc. read the accelerometer data? From my perspective the first question is how do you want this to be on air, and how will this be handled by the clients. Once you have decided that, then you can look into the implementation.
Regarding the implementation, it should be possible to update the advertisement packets more often than is done by the Eddystone example, inserting some other custom packets. I know for example that people have combined the Eddystone example and Beacon example (essentially an iBeacon). Unfortunately we do not have such an example, though.
