I'd like to combine Bayesian and non-parametric (e.g. XGBoost) models, with the goal of getting a probability distribution over my target variable rather than a point estimate. I have a prior, and I have some non-parametric models that produce reasonable results. My best guess is something like fit a simple Bayesian regression model and use the non-parametric model estimates as inputs.
Is there a more effective or more principled way to do this though?