What are your doses? As far as nolva (and this would apply to any antiE) affecting gains, the only gains you don't get are those that are estrogen related, ie. the water bloat. But as far as lean muscle, there should be no difference. How is your diet and training? You may want to consider dropping the nolva, unless you are susceptible to gyno or bloat. But it is up to you. You could keep running it, and go for a more defined look. But I don't think you need to go over 20mg/d.