The following is a generic answer but it applies to any car that has hydraulic valve lifters. I do not know if your car does but if it does then the following applies:
It is normal for any hudraulic valve lifter to be noisy at startup especially if the car has been sitting for too long, such as overnight or more. The reason is that the oil inside the lifter gets bleed out by the pressure of the valve spring, and until it gets filled up again the excesive valve clearance will result in some increased noise. The weight of the oil may also contribute to this effect.