To instantiate a Swift class dynamically using NSClassFromSwift. This works for ObjC as well as pure Swift classes.

NSClassFromSwift.swift

class YourClass {
    required init() {
    }
    func saySomething() {
        print("Hi!")
    }
}

if let classType = NSClassFromString("APPNAMEORMODULE.YourClass") as? YourClass.Type {
    let object = classType.init()
    object.saySomething()
}