They can be exactly the same. With Generalized Regression, you can choose Poisson with Maximum Likelihood estimation and the results will match the Generalized Linear Models Poisson regression with a Log Link function.

With Generalized Regression you have different estimation methods such as Maximum Likelihood, Lasso, Elastic Net, Ridge, Double Lasso, etc. With Generalized Linear Models you have only Maximum Likelihood Estimation. Also, with Generalized Regression you have a much greater choice of distributions to pick from.

Dan Obermiller