Let’s find horizontal asymptotes with help of the limits of this function at x->+oo and x->-oo
$$\lim_{x \to -\infty} \tan{\left(\operatorname{asin}{\left(x \right)} + 1 \right)} = \tan{\left(1 + \infty i \right)}$$
Let's take the limitso,
equation of the horizontal asymptote on the left:
$$y = \tan{\left(1 + \infty i \right)}$$
$$\lim_{x \to \infty} \tan{\left(\operatorname{asin}{\left(x \right)} + 1 \right)} = \tan{\left(1 - \infty i \right)}$$
Let's take the limitso,
equation of the horizontal asymptote on the right:
$$y = \tan{\left(1 - \infty i \right)}$$