most is safe during pregnancy. keeping ventalation is always good with nail polish and hair dye. a lot of salons prefer not to do dying on pregnant women, not because it is harmful it is because of the extra hormones you have running through your system could alter the outcome of the dye. some doc's differ on chocolate due to caffine same as coffee, tea and alchol.
all is safe in moderation. i would sit down with 12 candy bars and pig out but 1 or 2 a day shouldn't do much damage. as an example if it eases your mind. my 1st pregnancy i drank ice tea and coffee, had a glass of wine on thanksgiving, christmas, new years and my birthday and my now 17m old daughter is ahead of her marks and doing great. and yes i had to have some chocolate bars, dyed my hair and painted my nails too.