Just wondering since it had a TD release I think. A very expensive TD game if I recall.
Blud
Umm, no.  Outside of the general theme, they share nothing.  

Just a smidgen of research would have shown you that 
Cotton was made by Success, first for the arcades and then ported to the PCE (among others); 
Magical Chase was made by Quest for the PCE and later ported to the GBC; and if you check out screen shots and/or youtube footage, you'll find that they are very different graphically (
Cotton is much more dark and moody than the cartoonish and colorful 
Magical Chase).