Always getting "RETURN-FROM: no block named NIL is currently visible"

Please indent your code in a Lisp way (this can be done automatically in many editors, like Emacs):

(defun take-n (lst i)
  (setf newlst '())
  (dotimes (n i)
    (setf newlst (cons (car lst) newlst))
    (print (cons (car lst) newlst))
    (setf lst (cdr lst)))
  (return newlst))

(print (take-n '(1 2 3) 2))

Do not setf a variable that was not declared beforehand: (setf newlst '()) here refers to a hypothetical global variable newlst, but in a function you should strive to only have local state. You introduce variables in a block using let, as follows:

(let ((new-list ()))
  ...
  ;; here you can setf new-list if you need
  ...)

(setf newlst (cons (car lst) newlst)) can also be written (push (car lst) newlst), but please do not use overly abbreviated names; you can use list and new-list, for example.

return makes a return to the enclosing block named nil, but here you have no such block. Instead, defun introduces an implicit block named like the function you define, i.e. you have implicitly:

(block take-n
  ...)

So if you wanted to return from it, you would need to do (return-from take-n newlst).

BUT, you do not need to return since the last form being evaluated in the function is the value associated with the function call anyway.