"Macht nichts" is exactly the same idiom as the French "ça ne fait rien". The pronunciation I learned (Palatinate, age of about 2; my father studied at Heidelberg for a year) uses a front ch which is very un-English, and an English speaker without training would probably assimilate it to an x (or possibly to makt nikts by way of a back ch).

Odd what gets preserved. I grew up referring to a Volkswagen using the German pronunciation and "Entschuldigen Sie mich, bitte" but little else (other than some remembered children's stories like Max und Moritz) untill I studied German formally in High School.